PROJECT SUMMARY/ABSTRACT The applicant, Dr. Sarah Purcell, received graduate training in energy metabolism and body composition as it pertains to nutritional status in individuals with newly-diagnosed cancer. Dr. Purcell's long-term goal is to develop an independent research program that investigates energy balance as it relates to both nutrition and exercise interventions in clinical populations, including cancer and obesity. Examining regulators of energy balance such as appetite and physical activity will facilitate the development of more effective strategies to mitigate fat mass gain, maintain physical function, improve quality of life and ultimately reduce the public health burden of obesity. To help Dr. Purcell meet this goal, she has initiated postdoctoral research to investigate in how components of energy balance such as appetite, energy intake, and non-exercise activity are affected by structured exercise. Dr. Purcell and her mentoring team have developed a comprehensive training plan that will build upon her expertise in nutritional oncology while expanding her knowledge of energy balance in the context of exercise interventions, obesity, and oncology. Dr. Purcell?s primary training objectives include: 1) Improve theoretical knowledge of energy intake regulation, exercise, metabolism, and biostatistics, 2) Develop new research skills, 3) Lead a human intervention trial, 4) Enhance her professional development and network, and 5) Improve communication skills, publication record, and grantsmanship. To achieve these goals, Dr. Purcell?s proposed research project will 1) Examine the feasibility and acceptability of combining aerobic exercise training with an ongoing resistance exercise training program compared to resistance training alone, and 2) Elucidate potential alterations in appetite, energy intake, energy expenditure, and non-exercise physical activity during twelve weeks of combined aerobic/resistance exercise compared to a sedentary control condition among stage I-III breast cancer survivors. These activities will lead to several first-author publications and provide preliminary data to support continued mentored career development funding (i.e. K01). Data arising from this project will also inform the rationale and design of continued research aimed at understanding whole-body mechanisms of energy balance regulation in response to exercise training. Dr. Purcell will also have several opportunities for co-authorship within her sponsor?s and co-sponsor?s laboratories and other collaborators at the University of Colorado. Collectively, these activities will provide an unprecedented opportunity to develop Dr. Purcell?s research knowledge and skills, while providing a foundation for a successful independent research career.